The overall goal of this STTR project is to develop and test a new treatment for PTSD that will use Virtual Reality Technology to simulate the traumatic event. Phase I will be directed toward developing virtual environments essential to the treatment of PTSD following terrorist incidents or disasters and conducting a preliminary study of feasibility. An overarching goal of this project will be to develop a virtual environment that is flexible and can be adapted for use following future terrorist incidents or disasters (e.g., earthquakes, floods, fires). Each year millions of people worldwide experience a disaster or terrorist incident. While each event is unique, there are common elements of many disaster scenarios. For example, escape from a building following a terrorist incident, earthquake or fire; the sounds of emergency services vehicles; loss of electric power; smoke; etc. To be cost-effective, virtual simulations for disasters should be adaptable so that the software can be reconfigured rapidly for use following future disasters and terrorist incidents. This project will focus on the use of the configurable virtual reality environments in the treatment of chronic PTSD following the World Trade Center (WTC) attack of September 11, 2001.